This book has been written in response to the many physicians and scien tists working on the development of biological approaches to providing therapies for many orthopaedic disorders as well as to improving the healing of many tissues of the musculoskeletal system. The first goal of this book is to make the language compatible between the bench scientist and the clinician working in orthopaedic and sports medicine in order to cover specific areas of the orthopaedic discipline where the treatment can be improved and/or changed by the advancements in molecular medicine. Advancements in molecular biology, which encompass the study of the genetic basis of disease, have produced new diagnostic methods and drug therapies for genetic diseases and acquired disorders. The growth in the understanding of human genetics has also led to the initiation of many human gene therapy experiments. Although many approved therapeutic clinical trials using this new technology have been performed in the last ten years, the first clinical trial using this technology in the area of orthopaedics was performed at the University of Pittsburgh.